Gas Matrix Piezoelectric Ultrasound Array Transducer

ABSTRACT

A phased ultrasonic transducer and method for transmitting sound or ultrasound through a gaseous medium into a solid spectrum with ultrasound beam steering and focusing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.15/670,332, filed Aug. 7, 2017, which claims priority to U.S.Provisional Patent Application No. 62/372,847, filed Aug. 10, 2016, thedisclosures of which are hereby incorporated in their entirety byreference.

BACKGROUND OF THE INVENTION Field of the Invention

This disclosure is in the field of piezoelectric transducers forultrasound devices, more particularly, phased ultrasonic piezoelectrictransducers.

Description of Related Art

Transducers are devices that transform input signals into output signalsof a different form. In ultrasound devices, they transform signals ofelectric energy into acoustic energy or produce electrical signals fromabsorbed sound waves. In the fields of non-destructive testing ofmaterials, biomedical, non-invasive diagnostics, and ultrasonic powergeneration, it is highly desired that the source (transmitter) ofultrasound, that is, the transducer device, be characterized by hightransduction in the medium of transmission. It is further desirable thata transducer device be capable of transmitting a phased array in thesame way.

Both conventional contact and liquid immersion transducers andtechniques are well-known in medical diagnostic procedures and inmaterials testing. These transducers include both linear and phased.However, such transducers tend to be relatively expensive and generallyof larger form factor, conducive to hand-held devices, but notpractically adherable to a patient or test material. As such, a numberof potentially useful medical therapies or non-destructive testingapplications are not easily achievable.

It is thus desirable that a phased transducer exists of low profile andsmall form factor, such that it could be placed directly onto a patientor a test material for continuous therapy or monitoring. This wouldavoid the need for trained technicians to administer ultrasound therapyin a clinical setting. For non-destructive testing applications, thiscould allow for sophisticated and high performance transducers to beplaced long-term on aircrafts or other objects for structural healthmonitoring.

SUMMARY OF THE INVENTION

Briefly, according to this disclosure, there is provided a phasedultrasonic transducer based on the disclosures of U.S. patentapplication Ser. Nos. 09/446,058, 10/758,782, 10/337,531, and11/815,363, now U.S. Pat. Nos. 6,311,573, 7,084,552, 7,382,082 and7,791,253, respectively, the contents of which are incorporated hereinby reference.

According to one example of this disclosure is a phased ultrasonictransducer for continuous monitoring that can include a plurality ofindividual piezoelectric rods, where the individual piezoelectric rodshave a top and a bottom and can be separated from one another by apredetermined distance. A printed circuit board can have electrodesprinted on the printed circuit board, where the electrodes can bedivided into segments such that each segment is connected to anindividual piezoelectric rod of the plurality of individualpiezoelectric rods and a common conductive electrode plate can beconnected to the bottom of the plurality of individual piezoelectricrods. A acoustic impedance matching layer can be bonded to the commonconductive electrode plate such that the common conductive electrodeplate is between the acoustic impedance matching layer and the pluralityof individual piezoelectric rods, and a multipin connector can beconnected to an end of the printed circuit board, such that the multipinconnector can be connected to an ultrasound excitation and signalamplification electronic system.

In another example, the plurality of individual piezoelectric rods canbe separated by nonconductive material. In another example, thecombination of an individual piezoelectric rod and a segment ofelectrodes can be a channel.

In another example, the shape of the individual piezoelectric rods inthe core can be square, circular, elliptical, hexagonal, or any othershape. In another example and further relative to their configuration,the individual piezoelectric rods can be orderly or randomly placed inthe core.

According to another example of this disclosure is a method fortransmitting sound or ultrasound through a gaseous medium into a solidspecimen. This method can include using a phased ultrasound transducerfor continuous monitoring. In another example, this method can includeusing a 3D printing method to fabricate a plurality of individualpiezoelectric rods, a plurality of electrodes, and a acoustic impedancematching layer. The method can further include that the plurality ofindividual piezoelectric rods have a top and a bottom and can beseparated from one another by a predetermined distance. The electrodescan be printed on a printed circuit board and the electrodes can bedivided into segments such that each segment can be connected to anindividual piezoelectric rod of the plurality of individualpiezoelectric rods. This method can further include that a commonconductive electrode plate can be connected to the bottom of theplurality of individual piezoelectric rods, and the acoustic impedancematching layer can be bonded to the common conductive electrode platesuch that the common conductive electrode plate can be between theacoustic impedance matching layer and the plurality of individualpiezoelectric rods. A multipin connector can be connected to an end ofthe printed circuit board, and the multipin connector can be connectedto an ultrasound excitation and signal amplification electronic system.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a schematic cross-section of the gas matrix piezoelectricultrasound array transducer according to this disclosure.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The cross-section of an example of a gas matrix piezoelectric ultrasoundarray transducer is illustrated in FIG. 1. The individual rods ofpiezoelectric materials 1 can be separated from one another by apredetermined distance and have a top and a bottom. The separation ofthe individual rods of piezoelectric materials 1 can be by anonconductive material such as epoxy or rubber such as in the PolymerMatrix Piezoelectric (PMP) composite, or can be a solid piezoelectricmaterial that is scribed or etched on one surface in such a manner thatall adjacent circles or squares or any other shape of the piezoelectricmaterial is isolated from one another. As further seen in FIG. 1, aprinted circuit board (PCB) 3 can have electrodes 2 printed on the PCB3. The electrodes 2 can be separated into segments such that a segmentof electrodes can be connected to individual rods of piezoelectricmaterials 1. The bottom or far-side of the individual rods ofpiezoelectric materials 1 of the surfaces of the PMP or the solidpiezoelectric material is connected to a common ground electrode plate 4or thin or thick conductive film.

The electrode plate can be bonded to a acoustic impedance matching layer5 for suitable transmission in the propagating medium such as water,solid, or even in air, or other gases, such as described in, but notlimited to, U.S. Pat. No. 7,382,082.

Still referring to FIG. 1, the PCB or other individuallychannel-isolating electrode can be connected to a multipin connector 6or other circuitry, which is connected to a suitable ultrasoundexcitation and signal amplification electronic system. The system couldhave control over each individual channel or combination of channels asdesignated by the PCB (or other channel isolating electrode), to allowfor phased steering and focusing, or active control of channels to beexcited or inactivated as desired.

Through control of each piezoelectric rod (channel), the device canexhibit ultrasound beam steering and focusing.

The invention claimed is:
 1. A method for creating an ultrasonictransducer for continuous monitoring, the method comprising:fabricating, by a 3D printing method, a plurality of individualpiezoelectric rods, electrodes, and matching layers, wherein theplurality of individual piezoelectric rods have a top and a bottom andare separated from one another by a predetermined distance; theelectrodes are printed on a printed circuit board; the electrodes aredivided into segments such that each segment is connected to anindividual piezoelectric rod of the plurality of individualpiezoelectric rods; a common conductive electrode plate is connected tothe bottom of the plurality of individual piezoelectric rods; anacoustic impedance matching layer is bonded to the common conductiveelectrode plate such that the common conductive electrode plate isbetween the acoustic impedance matching layer and the plurality ofindividual piezoelectric rods; a multipin connector is connected to anend of the printed circuit board; and the multipin connector isconnected to an ultrasound excitation and signal amplificationelectronic system.
 2. The method of claim 1, wherein the plurality ofindividual piezoelectric rods are separated by nonconductive material.3. The method of claim 1, wherein the combination of an individualpiezoelectric rod and a segment of electrodes is a channel.
 4. Themethod of claim 1, wherein each segment comprises a plurality ofelectrodes connected to the individual piezoelectric rod of theplurality of individual piezoelectric rods.